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Meeting Minutes
This page will serve as a meeting log. June 18 *Autodesk Inventor training in assemblies, *Creating parts with the Sheet Metal tools, *Performing stress analysis on parts *Introduction to Monocoque concepts June 22 *Parameters in Autodesk Inventor *Demonstration of bending polycarbonate *Announcement and *work on design challenge #1: a polycarbonate monocoque arm at 20% of Logomotion scale. June 25 *Work on design challenge #1 *Practiced beinding polycarbonate using a piece designed for one of the design challenge #1 arms. This was much faster and easier with a new heatgun. June 29 *Short cantilever beam design challenge. This showed the importance of accounting for buckling in the design of structures. *More practice making long bends in polycarbonate. Refined techniques to mak e consistently clean bends even 12" long. Read about bending polycarbonate on the Polycarbonate page. July 2 *Designed and prototyped a Geneva Drive. July 6 *Evaluated 20 Geneva Drive approaches (link) for potential robotics applications. Considerations included torque, gear reduction, fabrication methods, combat robustness, and 'back drive" prevention *Choose to continue with the previously tested design, started thinking about the math necessary to optimize the design. July 9 *Started work on the Elevator Upgrades project. Erin and Jay wrote equations to find the force required to pull up the lift at the desired speed given its height, mass, etc. *Wrote a python script to calculate the (nondimensionalized) effect of a Geneva Drive "gearset" on a system, given a few general input parameters. *For the next meeting, we are planning on participants continuing to work on their mechanisms and beginning to size up the effort to reassemble and understand the mechanisms on FRC team 3630's 2011 robot CJ that went to the Championship this past April. July 13 *Discussed the performance and design of CJ. *Began rewiring CJ in order to clean it up and fix a problem with the cRIO wiring. July 16 *Mounted the elevator on CJ (it was removed for shipping). *Completed rewiring of CJ. *Ran elevator from the battery, discussed its performance, recorded video to analyze the performance. This is documented on the Elevator Upgrades page. July 20 *Successfully completed full test of CJ's teleoperated capabilities (sans-minibot): holonomic driving, manual elevator, arm, and gripper control, assisted elevator and arm control (using the "box" of buttons). *Debugged the cRIO error "line not configured for output". Solution was to plug a servo into the port where the code expected a reference to the minibot servo. July 23 *Encountered a problem with (any) arm control. The cause was discovered to be the "whiskers" on the gripper tripping the upper "end of travel" limit switch. *Encountered a problem with assisted (using "the box") arm control. The solution was to ensure that "the box" is plugged in before compiling/downloading code to the robot. *Discussed the elevator upgrades. Choose to use a Gas Spring as a counterweight. Sized the spring and ordered it, along with mounting hardware. *Completed and mounted detachable mecanum fenders (to prevent off-field debris from getting in the control systems) July 27 *Began relabling CJ's electrical and controls system (primarily for demonstration and teaching purposes) *Temporarily replaced CJ's rubber band counterweight system with a gas spring for testing. The resulting performance was not as expected, however the cause of this is still under investigation. July 30 *Assembled, wired, and mounted the pan-tilt camera setup on CJ. *Installed a 2nd digital sidecar (using cRIO slot #6) on CJ. This is needed for the camera setup, but will also help to ensure CJ functions as a test platform in the future. *Programmed CJ's pan-tilt camera with three modes: manual (nothing), minibot (looks at minibot), and elevator (automatically follows elevator position). *Reconfigured CJ's wireless device to work in "access point" mode for wireless programming and driving (this must be done to all "radios" post-competition). *Recieved Mia, and Astra's arm. Began sizing up the repair work, started electrical work. *Brought CJ to Laura K's graduation party for a demo. August 3 *Completed wiring Mia *Mounted Astra's arm on Mia. *Tested CJ's elevator with a gas shock, 6:1 pulley system. Concluded that friction in the pulley system is the cause of failure. *Reinstalled CJ's rubber band counterweight system (removing the gas spring) *Completed relabeling CJ *Briefed team members on new controls due to camera code upgrades August 6 *Modified CJ's covers to be compatible with the camera mount. *Debugged an electrical issue with CJ's arm control box. The problem appears to be a missing ground reference. *Test drove CJ from anothe room (out of sight), using the live camera feed and a spotter (for safety). *Mounted a simple counterweight on Mia's arm. *Updated 2498's classmate and cRIO to the correct software/firmware versions. *Downloaded early arm code onto Mia, successfully demonstrated basic control and the effectiveness of the counterweight. *Installed polycord to drive Mia's gripper. August 10 *Added guide wires, a zip tie to minimize the "wiggle" in Astra's arm. *Mounted sensors on Astra's arm: *A bumper switch in the gripper to detect tubes *A hall-effect sensor along the arm drive chain to provide rough arm control (it was determined that even though the "resolution" is too low to provide accurate control, this can still be used to learn about the sensor) *Two limit switches to detect the arm's highest and lowest positions, and to use for zeroing/homing the arm. *Made limit switch contact plates by bending polycarbonate. Successfully experimented with making small bends in thin (1/16") polycarbonate without heat. *Made significant progress on the code requried for closed-loop arm control. *Annie finished preparation of CJ for the trip to Lacrosse to recruit new schools, sponsors and mentors